JS - deep map function

Question

Underscore.js has a very useful map function.

_.map([1, 2, 3], function(num){ return num * 3; });
=> [3, 6, 9]
_.map({one: 1, two: 2, three: 3         


        

Answer 1

Here's the function I just worked out for myself. I'm sure there's a better way to do this.

// function
deepMap: function(data, map, key) {
  if (_.isArray(data)) {
    for (var i = 0; i < data.length; ++i) {
      data[i] = this.deepMap(data[i], map, void 0);
    }
  } else if (_.isObject(data)) {
    for (datum in data) {
      if (data.hasOwnProperty(datum)) {
        data[datum] = this.deepMap(data[datum], map, datum);
      }
    }
  } else {
    data = map(data, ((key) ? key : void 0));
  }
  return data;
},

// implementation
data = slf.deepMap(data, function(val, key){
  return (val == 'undefined' || val == 'null' || val == undefined) ? void 0 : val;
});

I cheated on using underscore.